Identification of a novel SH3PXD2B::FER fusion in a case of plexiform myofibroblastic tumor and review of the literature.

Fibroblastic/myofibroblastic tumors encompass a wide spectrum of lesions. Among them, plexiform myofibroblastoma (PM) represents a rare and distinctive entity recently described as mostly occurring in children and with a favorable prognosis. Histologically, PM shows SMA, CD34, and desmin expression in most cases, while it is negative for β-catenin and S100.

Reappraisal of soft tissue myoepithelial tumors by DNA methylation profiling reveals an epigenetically distinct group of mostly fusion-driven neoplasms.

Soft tissue myoepithelial tumors (METs) are diagnostically challenging tumors that require careful histologic and immunohistochemical characterization for accurate classification. Nearly half of METs show recurrent EWSR1 or FUS gene rearrangements with a diverse set of fusion partners. The diversity of fusion partners and lack of known driver abnormalities in many cases raises the question of whether METs represent a uniformly distinct tumor entity.

LMNA::NTRK1 and PRDX1::NTRK1 Atypical Spitz Tumor: A Report of Two Additional Cases With Histological, Immunohistochemical, and Molecular Insights.

Over the past decade, advancements in molecular biology have contributed to changes in the diagnostic classification of Spitz neoplasms, including Spitz nevi, atypical Spitz tumors, and Spitz melanomas. The recent World Health Organization classification of skin tumors identifies fusion kinases, including NTRK1, NTRK2, and NTRK3, as critical drivers of these lesions. New fusion genes have continued to expand the spectrum of known molecular alterations, particularly within the category of Spitz NTRK-rearranged lesions.